课程文献中心 更多>>

关键词： OLED   MR-TADF   Indolo[3,2,1-jk]carbazole   N-doping   Substituents engineering  

摘要：

• •
  A MR-TADF scaffold (NICz) is constructed via dual nitrogen-atom meta-doping of indolo[3,2,1-jk]carbazole (ICz).
• •
  The developed emitters realize deep-blue narrowband MR-TADF emission (426–440 nm, FWHM = 32–45 nm).
• •
  The corresponding OLEDs achieve a maximum external quantum efficiency of up to 32.2%.

关键词： 1-Bit DACs   Bit error rate   Constructive interference   Massive MIMO   Nonlinear programming   Precoding  

摘要： This paper studies the precoding design for the downlink of massive multiple-input multiple-output (MIMO) systems under phase shift keying (PSK) modulation, where the base station (BS) employs 1-bit digital-to-analog converters (DACs) to reduce system power consumption. We focus on constructive interference (CI)-based precoding under 1-bit constraints. The symbol-scaling CI-based precoding optimization problem is first formulated and then recast as a mixed-integer nonlinear programming (MINLP) problem. We then transform the original problem into a more tractable augmented Lagrangian dual problem by grouping constraints and introducing a quadratic penalty term. We also establish the strong duality between the dual problem and the primal problem. Due to the non-differentiability of the dual function, we propose a projected subgradient ascent (PSGA) algorithm that alternately updates the dual variables and the Lagrange multipliers. Furthermore, an efficient proximal block coordinate descent (PBCD) algorithm is proposed to solve the Lagrangian function minimization subproblem in the PSGA algorithm. Finally, we analyze the computational complexity and provide a detailed convergence proof for the proposed PSGA-PBCD algorithm. Simulation results demonstrate that the proposed PSGA-PBCD algorithm achieves superior bit error rate (BER) performance with a reasonable computational cost.

关键词： Antimalarial   Atovaquone-resistant parasites   In silico study   Plasmodium falciparum   Rhinacanthins   Rhinacanthus nasutus  

摘要： Malaria remains a major global health challenge, worsened by drug-resistant Plasmodium falciparum. Natural products remain key sources for novel therapeutics. Rhinacanthus nasutus, a Southeast Asian medicinal plant, produces rhinacanthins naphthoquinones with diverse pharmacological activities but limited exploration in malaria. This study evaluated the antimalarial activity, cytotoxicity, and mechanism of four rhinacanthins from R. nasutus against drug-sensitive and drug-resistant P. falciparum. Roots of R. nasutus were extracted to yield rhinacanthins B, C, D, and N. In vitro activity was assessed against P. falciparum 3D7 and atovaquone-resistant strains using SYBR Green I assay. Cytotoxicity was determined in Vero and KB cells via sulforhodamine B assays. Mechanistic insights were obtained through molecular docking and dynamics simulations targeting the mitochondrial cytochrome bc1 (cyt bc₁) complex. All four rhinacanthins inhibited P. falciparum 3D7 proliferation with IC₅₀ values of 27–406 nM, with rhinacanthin C and

来源 ScienceDirectJournal ScienceCitationIndex... 详细信息

关键词： Barents sea   Marginal ice zone   Ocean eddies   SAR imaging   Sentinel-1   Spitsbergen bank  

摘要： Here we compile a detailed record of eddies and examine their seasonal variability over the Spitsbergen Bank in the northwestern Barents Sea using spaceborne Sentinel-1 A/B synthetic aperture radar (SAR) data acquired in 2018. Analysis of 3070 SAR images enabled to register 1758 eddy manifestations in the marginal ice zone (MIZ) and 1631 eddy signatures in the open water (OW). Eddies were observed within a range of diameters of 0.2-40 km with diameters of MIZ eddies being twice larger than those of OW eddies. When converted to eddy radii, their values, peaking at 2-4 km, are of the same order or below the local Rossby radii values, meaning that submesoscale eddies dominate in the record. We note a strong seasonal variability of eddy radii/diameters and the ratio of cyclones to anticyclones. The eddies were present in all seasons showing an approximate parity in eddy generation intensity in the surface layer between winter and summer. A well-pronounced seasonality of SAR-derived eddy intensity has similar tendencies with that of eddy kinetic energy in the surface layer of the Eurasian Arctic. Generation mechanisms seem to be identical in winter and summer and include baroclinic instability of main currents, topographic/orographic and frontal generation. A notable feature of eddy distribution over the Spitsbergen Bank in all seasons is a higher eddy intensity over its eastern flank compared to the western one. A possible reason behind the noted asymmetry is linked to presence of opposing currents and the Polar Front over the eastern flank. Eddies were also detected very frequently in Storfjorden, south of Edge Island and near Hopen Island. The MIZ eddies were recorded during eight months of the year peaking in February, and being spatially limited by a 200-m isobath. The OW eddies were widely dispersed across the study domain peaking in August and tending to accumulate in regions of relatively weak surface currents. In summer, about 20-25% of them were observed within

关键词： Penicillium-derived exopolysaccharides   Cyclophosphamide   Immunomodulation   Intestinal barrier   Gut microbiota   Metabolomic  

摘要： Exopolysaccharides(EPS)produced by endophytic fungi isolated from Cyclocarya paliurus have been reported to exhibit immunostimulatory activity in vitro;however,its in vivo immunoregulatory effects remain unclear.The study aimed to investigate its protective effects and mechanisms against cyclophosphamide(CTX)-induced immunosuppression and intestinal injury in mice.EPS treatment mitigated body weight loss,thymic atrophy,and splenomegaly,while promoting intestinal repair by modulating cytokine secretion,T cell,goblet cell,MUC2,and tight junction proteins through activation of the Nrf2/HO-1 signaling pathway.Furthermore,gut microbiota and metabolomic analyses revealed that EPS ameliorated CTX-induced dysbiosis,corrected microbial translocation and niche imbalance,and restored lipid,bile acid,and amino acid metabolism.Collectively,these findings indicate that Penicillium-derived EPS can alleviate immunosuppression and intestinal injury by regulating gut microbiota composition,restoring intestinal barrier integrity,and re-establishing metabolic homeostasis.This study provides theoretical support for the potential application of fungal polysaccharides as immunomodulatory agents and functional food ingredients.

关键词： Double perovskite   Electrochemical sensing   Impedance   Powder X-ray diffraction   Semiconducting behavior and lactic acid  

摘要： A series of Fe-substituted Ba₂Mn_1-xFe_xTeO₆ (0.0 ≤ x ≤ 1.0) double perovskite oxide materials were synthesized via a sol–gel route and systematically investigated to establish structure–property–electrochemical sensing relationships. Powder X-ray diffraction (XRD) analysis confirmed the formation of single-phase trigonal perovskites with R-3m symmetry across the composition range. Progressive Fe substitution led to a marked enhancement in dielectric and charge-transport properties, with the dielectric constant increasing from 69 to 141 and electrical conductivity rising from 10⁻¹⁰ to 10⁻⁹ S m⁻¹, accompanied by a reduction in resistivity from 10⁹ to 10⁸ Ωm. Impedance analysis revealed non-Debye relaxation behavior with relaxation times in the range of 2.61–3.97 ms and a systematic decrease in charge-transfer resistance upon Fe incorporation. Current–voltage (I–V) measurements further indicated a transition from insulating to semiconducting behavior with increasing Fe content. Exploiting these enhanced electrochemical properties, Ba₂Mn_1-x Fe_xTeO₆ (0.0 ≤ x ≤ 1.0) was employed for the first time as a non-enzymatic electrochemical interface for lactic acid (LA) detection in human saliva. Electrochemical evaluation using cyclic voltammetry, differential pulse voltammetry, and impedance spectroscopy demonstrated composition-dependent sensing performance, with Ba₂FeTeO₆ exhibiting the highest sensitivity (0.306 μA mM⁻¹ by CV and 1.28 μA cm⁻² mM⁻¹ by DPV). The sensor enabled LA detection over a wide concentration range, achieving a limit of detection of 0.12 mM in the 100–700 mM range and significantly enhanced sensitivity at micromolar concentrations. Ba₂FeTeO₆ sensor delivered limits of detection and quantification as low as 0.270 and 0.821

摘要： BN-embedded dibenzo[fg,op]tetracenes (BNDBTs) were synthesized via a borylative cyclization cascade reaction of 10-alkynyl-1-phenylphenanthren-9-amines and phenyldichloroborane (BCl₂Ph) in toluene at 100 °C. The used starting materials 10-alkynyl-1-phenylphenanthren-9-amines can be synthesized from 2′-formyl-[1,1':3′,1″-terphenyl]-2-carbonitrile via a one-pot two-step reaction, including the formation of corresponding N-tosylhydrazones and subsequent CuI-catalyzed cascade cyclization. The photophysical properties of synthesized BNDBTs were also analyzed, which indicated that the fluorescence emission peaks of these compounds appeared at 450-470 nm, and dichloro-substituted BNDBTs owned the highest fluorescence quantum efficiency, which was 0.42.

关键词： (1-0)-3 single crystal piezocomposite   Dual-piezo-charge mechanism   Hydrostatic figure of merit   Piezoelectric ultrasonic transducers   Acoustic sensitivity  

摘要： Piezoelectric ultrasonic transducers(PUTs)are extensively used in diverse technological fields,yet further enhancement in acoustic sensitivity and hydrostatic figure of merit dhgh have plateaued in conventional 1-3 piezocomposites,whose structures have remained largely unchanged for decades.Herein,we report a(1-0)-3 single-crystal piezocomposite(SCPC)based on the[011]-oriented Pb(In_(1/2)Nb_(1/2))O_(3)-Pb(Mg_(1/3)Nb_(2/3))O_(3)-PbTiO_(3)(PIN-PMN-PT)single-crystal,featuring a dual-piezo-charge(DPC)mechanism arising from the piezoelectric and piezoelectret synergy effect.The ordered and polar 0-phase microholes with aligned dipoles are intentionally introduced in 1-phase piezo-pillars,yielding a uniquely low effective dielectric constant,reduced acoustic impedance,and DPC properties unattainable in conventional SCPCs.Both Simulations and experiments confirm that this DPC mechanism in(1-0)-3 SCPC enables an ultrahigh dhgh of~8089×10^(-15) m^(2) N^(-1),representing increases of 443.2%and 890.6%over commercial 1-3 SCPC and 1-3 piezoceramic composite,respectively.The engineered microhole structure and DPC strategy also significantly enhance underwater acoustic sensitivity while maintaining a broad−3 dB bandwidth of 130 kHz,crucial for maritime safety and collision avoidance.Meanwhile,the long-term testing further verifies the PUT’s operational stability.This design approach offers a promising pathway for next-generation piezocomposites and PUT technologies.